Microsoft Security Bulletin (MS00-025)

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Microsoft Security Bulletin (MS00-025)
- --------------------------------------

Procedure Available to Eliminate "Link View Server-Side Component"
Vulnerability

Originally Posted: April 14, 2000

Summary
=======
A procedure is available to eliminate a security vulnerability in
several web server products. The vulnerability could allow  a user who
has privileges on a web server to read certain files from other web
sites hosted on the same computer.

Frequently asked questions regarding this vulnerability and
the procedure can be found at
http://www.microsoft.com/technet/security/bulletin/fq00-025.asp

Issue
=====
Dvwssr.dll is a server-side component used to support the Link View
feature in Visual Interdev 1.0. By design, it provides  .asp files to
clients who have web authoring privileges on the server. However, it
does not properly restrict the files that  a web author can request,
with the result that a user who has web authoring privileges on one
web site could request .asp  files from anywhere on the server,
including other web sites hosted on it. However, even with this
vulnerability, the  component would only comply with the request if
the specific file granted read access to the user.

There are some significant restrictions to this vulnerability:
 - Only servers hosting multiple web sites could be affected by it
 - Only a user who has web authoring privileges for a site on the
   server could request a file. He would need to know the name and
   location of the file on the server.
 - The files would only be sent if their permissions granted read
   access to the particular user who requested them. In most cases,
   this would mean that the files granted read access to the
   Everyone group
 - Only .asp files (and global.asa, which is a special-case .asp
   file) could be retrieved.

Affected Software Versions
==========================
The affected component is part of Visual Interdev 1.0. However, it is
a server-side component, and is included in the  following products:
 - Windows NT 4.0 Option Pack
 - Personal Web Server 4.0, which ships as part of Windows 95 and 98
 - Front Page 98 Server Extensions

NOTE:
1. Windows 2000 is not affected by this vulnerability. Upgrading
   from an affected Windows NT 4.0 to Windows 2000 removes the
   vulnerability.
2. Installing Office 2000 Server Extensions on an affected server
   removes this vulnerability.
3. Installing FrontPage 2000 Server Extensions on an affected
   server removes this vulnerability.

Remediation
===========
To eliminate this vulnerability, customers who are hosting web sites
should delete all copies of the file Dvwssr.dll from  their servers.
The FAQ provides step-by-step instructions for doing this. The only
functionality lost by deleting the file is  the ability to generate
link views using Visual Interdev 1.0.

More Information
================
Please see the following references for more information related to
this issue.
 - Frequently Asked Questions: Microsoft Security Bulletin MS00-025,
   http://www.microsoft.com/technet/security/bulletin/fq00-025.asp.
 - Microsoft Knowledge Base article Q259799 discusses this issue
   and will be available soon.
 - Microsoft TechNet Security web site,
   http://www.microsoft.com/technet/security/default.asp.

Obtaining Support on this Issue
===============================
Information on contacting Microsoft Technical Support is available
at http://support.microsoft.com/support/contact/default.asp.

Revisions
=========
 - April 14, 2000: Bulletin Created.

- --------------------------------------------------------------

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LIMITATION MAY NOT APPLY.

Last updated April 14, 2000

(c) 2000 Microsoft Corporation. All rights reserved. Terms of use.

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